To protect persons in a motor vehicle against injury as a result of an impact by the motor vehicle against an object or the impact from another motor vehicle, it is common practice to provide an impact absorbing body or element between the bumper of the motor vehicle and the chassis or support frame thereof.
During an accident involving an impact, it is generally desirable and advantageous that the vehicle reduce its speed over the entire collision process to minimize the danger to persons within the vehicle. In other words the process of impact absorption should be substantially continuous over the entire collision process. For this purpose the strength reserve of the body of the vehicle should be fully utilized from the very beginning of the collision. This means that the deformation resistance from the beginning of the collision should be as high as possible to allow the greatest deformation work to be required from the inception of the collision.
This, of course, means that a substantially constant resistance force should be provided against the force of collision and in part the impact attenuator interposed between a bumper and the vehicle chassis supplies this function. There are various bumper supports which, in part by their deformation work, serve to maintain this constant force. Similar systems are provided also in the steering columns of the automotive vehicle. A major drawback of earlier energy absorbing or constant force supports for this purpose is that they generally are composed of a plurality of parts and thus must be assembled for use.